DIY Knock Detection

I was scouring the web in search of some affordable knock detection sensor, most products costing more then I cared to spend usually in the $200 to $600 range. I couldn’t believe how limited most of the products were for the amount of money they were charging. Essentially everything was a box that had some LEDs and a speaker for an alarm. Here’s some info on making a DIY knock detection device with a whisper 2000.

The case is opened by removing 3 self tapping screws. This reveals the “guts” of the whisper2000.

The mic is then removed from whisper2000, rewired to 5-10 feet of ext wire, and then glued onto a alligator style clip.

The clip is then placed somewhere on the engine to best detect knock. On the KA the clip should be placed as close as possible to the factory knock sensor. You’re then able to listen for knock via headphones.

This method looks and sounds crude, but I have read nothing but rave reviews of how well it actually works. Guys with data logging software are able hear knock before the factory knock sensor registers any. Of course for those of you that don’t want to use headphones, you could always connect the whisper2000 to an alarm and LED.

Now after some browsing and brainstorming I found this.

For $30 bucks plus a headphone extension cable, we get a unit with a self contained mic which removes all the BS involved with the above whisper2000. If I can buy a unit that lets me avoid soldering, I’m going to.

With this unit I believe we can attach it right under the intake manifold with the mic right over the knock sensor. This should give us a good signal, remove the need to rewire anything and the price is a hell of a lot better then the other knock monitors on the market that range from $200 to $600 and don’t do much besides turn on a light and make noise.

Also, if you want to data log the “knock” you can get a headphone splitter and connect another 3.5mm cable directly to your Line In slot on your sound card, it’s usually marked in blue with the line out marked in green.

Then simply select “start”, type the word ‘sound’ in the search box and Sound Recorder should be one of the choices. Select Sound Recorder and then click record when your ready to start.